There is a method for forming a so-called photonic crystal, which is a nano-order fine concavo-convex structure, in a light emitting device such as a light emitting diode or a laser diode in order to enhance the light extraction efficiency of the device (for example, see Patent Document 1). This method includes the steps of laminating an etching mask made of silicon oxide on a first nitride semiconductor layer and forming pores in the first nitride semiconductor layer via the etching mask by photolithography, thereby forming a fine concavo-convex structure in the first nitride semiconductor layer.